Buggy code:
public class nullSQLText { public static void main ( String [ ] args ) { } private static void dumpSQLExceptions ( SQLException se ) { } private static void derby522 ( Statement st ) throws Exception { System . out . println ( "Starting<seq2seq4repair_space>test<seq2seq4repair_space>for<seq2seq4repair_space>DERBY-522." ) ; st . execute ( "create<seq2seq4repair_space>table<seq2seq4repair_space>t1<seq2seq4repair_space>(i<seq2seq4repair_space>int)" ) ; st . execute ( "insert<seq2seq4repair_space>into<seq2seq4repair_space>t1<seq2seq4repair_space>values<seq2seq4repair_space>1,<seq2seq4repair_space>2,<seq2seq4repair_space>3,<seq2seq4repair_space>4,<seq2seq4repair_space>5,<seq2seq4repair_space>6,<seq2seq4repair_space>7" ) ; st . execute ( ( "create<seq2seq4repair_space>procedure<seq2seq4repair_space>za()<seq2seq4repair_space>language<seq2seq4repair_space>java<seq2seq4repair_space>external<seq2seq4repair_space>name<seq2seq4repair_space>" + ( "'org.apache.derbyTesting.functionTests.util.ProcedureTest.zeroArg'" + "<seq2seq4repair_space>parameter<seq2seq4repair_space>style<seq2seq4repair_space>java" ) ) ) ; nullSQLText . testCommentStmt ( st , "<seq2seq4repair_space>--" , true ) ; nullSQLText . testCommentStmt ( st , "<seq2seq4repair_space>--<seq2seq4repair_space>" , true ) ; nullSQLText . testCommentStmt ( st , "<seq2seq4repair_space>--<seq2seq4repair_space>This<seq2seq4repair_space>is<seq2seq4repair_space>a<seq2seq4repair_space>comment<seq2seq4repair_space>\n<seq2seq4repair_space>--" , true ) ; nullSQLText . testCommentStmt ( st , "<seq2seq4repair_space>--<seq2seq4repair_space>This<seq2seq4repair_space>is<seq2seq4repair_space>a<seq2seq4repair_space>comment\n<seq2seq4repair_space>--And<seq2seq4repair_space>another\n<seq2seq4repair_space>--<seq2seq4repair_space>Andonemore" , true ) ; nullSQLText . testCommentStmt ( st , "<seq2seq4repair_space>--\nvalues<seq2seq4repair_space>2,<seq2seq4repair_space>4,<seq2seq4repair_space>8" , TestUtil . isJCCFramework ( ) ) ; nullSQLText . testCommentStmt ( st , "<seq2seq4repair_space>--<seq2seq4repair_space>This<seq2seq4repair_space>is<seq2seq4repair_space>\n<seq2seq4repair_space>--<seq2seq4repair_space>\n<seq2seq4repair_space>--3<seq2seq4repair_space>comments\nvalues<seq2seq4repair_space>8" , TestUtil . isJCCFramework ( ) ) ; nullSQLText . testCommentStmt ( st , "<seq2seq4repair_space>--<seq2seq4repair_space>This<seq2seq4repair_space>is<seq2seq4repair_space>a<seq2seq4repair_space>comment\n<seq2seq4repair_space>--And<seq2seq4repair_space>another\n<seq2seq4repair_space>--<seq2seq4repair_space>Andonemore\nvalues<seq2seq4repair_space>(2,3)" , TestUtil . isJCCFramework ( ) ) ; nullSQLText . testCommentStmt ( st , "<seq2seq4repair_space>--<seq2seq4repair_space>This<seq2seq4repair_space>is<seq2seq4repair_space>a<seq2seq4repair_space>comment\n<seq2seq4repair_space>select<seq2seq4repair_space>i<seq2seq4repair_space>from<seq2seq4repair_space>t1" , TestUtil . isJCCFramework ( ) ) ; nullSQLText . testCommentStmt ( st , "<seq2seq4repair_space>--singleword\n<seq2seq4repair_space>insert<seq2seq4repair_space>into<seq2seq4repair_space>t1<seq2seq4repair_space>values<seq2seq4repair_space>(8)" , TestUtil . isJCCFramework ( ) ) ; nullSQLText . testCommentStmt ( st , "<seq2seq4repair_space>--singleword\ncall<seq2seq4repair_space>za()" , TestUtil . isJCCFramework ( ) ) ; nullSQLText . testCommentStmt ( st , "<seq2seq4repair_space>--<seq2seq4repair_space>leading<seq2seq4repair_space>comment\n(\nvalues<seq2seq4repair_space>4,<seq2seq4repair_space>8)" , TestUtil . isJCCFramework ( ) ) ; nullSQLText . testCommentStmt ( st , "<seq2seq4repair_space>--<seq2seq4repair_space>leading<seq2seq4repair_space>comment\n\n(\n\n\rvalues<seq2seq4repair_space>4,<seq2seq4repair_space>8)" , TestUtil . isJCCFramework ( ) ) ; nullSQLText . testCommentStmt ( st , "select<seq2seq4repair_space>i<seq2seq4repair_space>from<seq2seq4repair_space>t1<seq2seq4repair_space>--<seq2seq4repair_space>This<seq2seq4repair_space>is<seq2seq4repair_space>a<seq2seq4repair_space>comment" , false ) ; nullSQLText . testCommentStmt ( st , "select<seq2seq4repair_space>i<seq2seq4repair_space>from<seq2seq4repair_space>t1\n<seq2seq4repair_space>--<seq2seq4repair_space>This<seq2seq4repair_space>is<seq2seq4repair_space>a<seq2seq4repair_space>comment" , false ) ; nullSQLText . testCommentStmt ( st , "values<seq2seq4repair_space>8,<seq2seq4repair_space>4,<seq2seq4repair_space>2\n<seq2seq4repair_space>--" , false ) ; nullSQLText . testCommentStmt ( st , "values<seq2seq4repair_space>8,<seq2seq4repair_space>4,\n<seq2seq4repair_space>--<seq2seq4repair_space>middle<seq2seq4repair_space>comment\n2\n<seq2seq4repair_space>--<seq2seq4repair_space>end" , false ) ; nullSQLText . testCommentStmt ( st , "values<seq2seq4repair_space>8,<seq2seq4repair_space>4,\n<seq2seq4repair_space>--<seq2seq4repair_space>middle<seq2seq4repair_space>comment\n2\n<seq2seq4repair_space>--<seq2seq4repair_space>end\n" , false ) ; try { st . execute ( "drop<seq2seq4repair_space>table<seq2seq4repair_space>t1" ) ; } catch ( SQLException se ) { } try { <START_BUG> st . execute ( "drop<seq2seq4repair_space>procedure<seq2seq4repair_space>proc1" ) ; <END_BUG> } catch ( SQLException se ) { } st . close ( ) ; System . out . println ( "DERBY-522<seq2seq4repair_space>test<seq2seq4repair_space>completed." ) ; } private static void testCommentStmt ( Statement st , String sql , boolean expectError ) throws SQLException { } }

Fix:
st . execute ( "drop<seq2seq4repair_space>procedure<seq2seq4repair_space>za" ) ;